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Industrial-Size Eco-Roofs Near Portland Harbor

Two eco-roofts at the Gunderson train and barge manufacturing plant in Portland add about 3,500 square feet of habitat and stormwater control to the industrial property on the Willamette River.

I visited the Gunderson LLC rail and barge manufacturing facility today to talk with General Manager Mark Eitzen about his company’s pending contract to build barges for the Morrow Pacific coal export project.

On a side note, he mentioned his company’s pilot project building its own industrial-scale eco-roofing.

We climbed up to take a look, and the juxtaposition was stunning. Perched above acres of concrete and industrial machinery on the Willamette River (near the Portland Harbor Superfund site, no less) was a tranquil little garden just starting to sprout.

The Portland Tribune reported the project last year, after Gunderson built its first 1,000-square-foot rooftop, which cost $75,000 to build. The one in the photo above is the 2,500-square-foot model. Now the company is working on a third that probably be even bigger, Eitzen said.

“Obviously, we do a lot of industrial work here,” he said. “This creates an opportunity for wildlife to exist alongside our operations. We have an osprey we’ve adopted as well.”

I’d never seen an industrial-size eco-roof. But they’re becoming more common. The most famous in the U.S. may be this one at a Ford plant in Dearborn, Mich.

Weston Miller, urban horticulturist for Oregon State University, said Gunderson has an incentive to invest in eco-roofs because the city of Portland charges the company for stormwater flowing off its rooftops.

“If they can decrease that, they can decrease their costs,” he said.

An eco-roof also provides some unique benefits in an industrial area.

“They’re going to provide habitat in an otherwise pretty inhospitable place,” said Miller. “Soil ecology is able to break things down and provide a level of cleansing to the environment too.”

It’s a great idea, he said, but there are some maintenance costs for weeding and irrigating the gardens, and they do get heavy. The bigger they get, he said, the heavier they get.

“The weight gets so large it makes the structural engineering more expensive,” he said. “Most buildings weren’t built to sustain that extra weight.”

Eitzen said his pilot rooftops are testing the cost and value of the company’s design and that Gunderson is now looking at marketing them to other companies.

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